Solenoids are typically used as electromechanical valves, e.g., by controlling current in the solenoid to move a magnet within the solenoid. Other types of solenoids can involve a movement of an object within the solenoid. Solenoids can be used in charging circuits, but often the device being charged is part of the same circuit as a solenoid.
For wireless charging, two solenoids are typically placed side-by-side around a two arms of a magnetic core (transformer) and driven with an alternating current. Or, two solenoids are situated with one on top of each other and driven with an alternating current. In either case, a Lenz effect is produced by such operation, which can result in electric fields that oppose current changes, thereby adding a load to the system and resulting in lower efficiency.
Therefore, it is desirable to provide improved systems, apparatuses, and methods for using coils in induction.